1. Field of the Invention
This invention relates to an axle suspension system and more particularly to a drive axle suspension system utilizing a parallelogram-type suspension system. More particularly, in one embodiment, the axle suspension system of this invention combines the functions of upper control arms and a stabilizer bar and in another embodiment combines the functions of lower control arms and a stabilizer.
2. Description of the Related Art
In many conventional rear drive axle suspension systems for trucks, the opposite ends of the rear drive axle are secured to the frame members of the truck by leaf spring suspension systems. Although the leaf spring suspension systems have functioned well for many years, it is sometimes desirable to replace the leaf springs with air spring to enhance the load carrying characteristics of the suspension system.
One prior art axle suspension system is known as a parallelogram-type axle suspension system wherein a pair of upper and lower control arms are provided beneath each of the frame members of the truck with the forward ends of the control arms being pivotally secured to mounting brackets and with the rearward ends of the control arms being secured to axle supports. Although the parallelogram-type axle suspension systems have met with considerable success, a separate sway bar or stabilizer bar is sometimes required to control roll or sway movements. The need for a separate stabilizer bar involves additional mounting problems and expense.